ICD-10 Code A85.0 – Enteroviral Encephalitis (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code A85.0 – Enteroviral encephalitis
What it is
A85.0 identifies encephalitis caused by an enterovirus, meaning inflammation of the brain linked to a viral enteric infection. Use this code when documentation clearly states enteroviral encephalitis.
Clinical signs
Clinical features vary; refer to documentation. Typical encephalitis findings may include altered mental status, fever, seizures, headache, or focal neurologic deficits, but the record should support enteroviral cause.
When to use this code
Use A85.0 when the provider documents enteroviral encephalitis, viral encephalitis due to an enterovirus, or a confirmed enterovirus-related brain infection. It may also fit when cerebrospinal fluid or other evidence supports the diagnosis and the chart names the organism.
If the note only says “encephalitis” without a viral cause, check documentation before coding. Do not assume enteroviral etiology from nonspecific viral symptoms alone.
Do not use for
Do not use this code for meningitis, nonspecific viral infection, or encephalopathy without documented encephalitis. Check documentation if the record describes a different viral cause.
Coding tip
Code the documented organism exactly; if enterovirus is not stated, query or use the more specific confirmed diagnosis.